INVESTMENT SECURITIES (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015	Sep. 30, 2015
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 821,410	$ 778,261	$ 804,680
Gross Unrealized Gains	17,079	8,136	9,259
Gross Unrealized Losses	(365)	(3,212)	(2,554)
Fair Value	838,124	783,185	811,385
U.S. government sponsored agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	999	14,959	14,957
Gross Unrealized Gains	29	0	26
Gross Unrealized Losses	0	(69)	(15)
Fair Value	1,028	14,890	14,968
State, county and municipal securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	150,083	157,681	161,509
Gross Unrealized Gains	5,939	4,046	3,875
Gross Unrealized Losses	(28)	(411)	(519)
Fair Value	155,994	161,316	164,865
Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	28,924	5,900	5,901
Gross Unrealized Gains	194	145	150
Gross Unrealized Losses	(20)	(28)	(19)
Fair Value	29,098	6,017	6,032
Mortgage-backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	641,404	599,721	622,313
Gross Unrealized Gains	10,917	3,945	5,208
Gross Unrealized Losses	(317)	(2,704)	(2,001)
Fair Value	$ 652,004	$ 600,962	$ 625,520